How to Plant, Grow and Care For Viburnum Shrubs
Viburnums are a shrubby plant that can make a hardy addition to any garden space. Once established, they are fairly low-maintenance, and can grow across several hardiness zones. In this article, gardening expert Jill Drago shares her experience with viburnums and all aspects of their care.
Contents
Viburnums are a large group of flowering shrubs. Viburnums vary greatly within the genus, with no real characteristic tying them all together. These shrubs often have white flowers and almost always have colorful berries that follow the flowers.
These shrubs are native to a large part of North America, and because of this, they are typically pretty low-maintenance. Viburnums do not require much water once they are established and require little pruning if they are planted in the correct space.
Let’s learn about these native beauties! We will learn how to use it in your landscape, and how to grow it with ease. You’ll also get suggestions for a few popular varieties.
Viburnum Shrub Overview
Plant Type
Shrub
Diseases
Fungal
Attracts
Pollinators
Season
Spring Maturity
Date
5-10 years, varies
Hardiness Zones
2-9
Pests
Aphids, Thrips, Scale, Beetles
|
Maintenance
Low
Plant With
Azalea, Hosta, Hydrangea, Peony
Family
Adoxaceae
Growth Rate
Fast Growing
Don’t plant with
N/A
Genus
Viburnum
Soil Type
Well- Drained
|
Planting Depth
Crown of plant at soil level
Species
spp.
Native Area
North America
Watering Requirements
Low once established
Exposure
Full to partial sun
Plant Spacing
varies
Plant height
3-20 feet
|
Plant History
Viburnums are native to both North America as well as regions of Asia. It is a very large group of plants that consists of over 150 named species and countless varieties.
Viburnums are a funny group of flowering shrubs. There are countless species, but there isn’t any singular characteristic that ties the group together.
There are two similarities, however. Their fruit type is a drupe (fleshy fruit with a hard seed inside- think of a peach, but much smaller in the case of a viburnum), and their leaves are opposite. This means the leaves on either side of the stems grow directly opposite from each other from one growth point or node.
Cultivation
Viburnums are a large genus with over 150 different species. However, there are 10 species that are considered to be the most common and most loved.
Burkwood Viburnum
Viburnum x burkwoodii is a fragrant viburnum that is hardy in zones 4-8. This viburnum will grow from 8-10 feet tall and the foliage is semi-evergreen.
Korean Spice Viburnum
Viburnum carlesii may just be the most used viburnum. It is popular for its fragrant flowers. This speicies typically grows anywhere from 4-6 feet tall, however some varieties have been known to reach 10 feet. Korean Spice viburnum is hardy in zones 5-8.
David Viburnum
Viburnum davidii is another lovely option for your garden. This species grows in a nice mounded form growing from 3-5 feet tall. The flowers begin as pink and fade quickly to white. The berries are often blue and showy. David viburnum is hardy in zones 8 and 9.
Arrowwood Viburnum
Viburnum dentatum is a great viburnum for partial shade gardens. The flowers are white and are often followed by blue berries. Arrowwood viburnum will grow from 6-10 feet in zones 2-8.
Henry’s Viburnum
Viburnum henryi is easily trained into a tree form and will grow from 7-15 feet tall in partial sun. The leaves are evergreen and hold an attractive fall color. Grow this warm climate species if you are in hardiness zones 7-10
Wayfaring Tree
Viburnum lantana is a tall viburnum species that can be a bit leggy but still has beautiful flowers. Grow this species in full to partial sun and it will reach between 10 and 15 feet in height. Grows best in zones 4-7.
Nannyberry
Viburnum lentago is a drought-tolerant plant that boasts white flowers that will last into the fall. Once the flowers have dropped, there will be a large number of berries present on the shrub.
Grow nannyberries in full to partial sun, and the shrub will grow from 14-16 feet tall. This species grows best in hardiness zones 3-7.
Snowball Bush
Viburnum opulus boasts snowball-like flowers. Many viburnums have these rounded flowers, but this is the most common species.
This species is considered to be invasive in some areas, so check your invasive plant list before purchasing. The snowball bush will grow from 8-15 feet in full or partial sun. Plant this species in zones 2-8.
Leatherleaf Viburnum
Viburnum rhytidophyllum is a semi-evergreen viburnum, dropping its leaves in cooler climates. Its flowers are flat rather than ball-shaped but still beautiful. The leatherleaf viburnum will grow from 6-15 feet tall in full to partial sun. Grow this species in zones 5-8.
Laurustinus Viburnum
Viburnum tinus is an evergreen viburnum with pink to white flowers. This species will grow from 6-12 feet tall in full to partial sun. Grow confidently in hardiness zones 7-9.
Propagation
The easiest and most successful way to propagate your viburnums is through taking softwood or hardwood cuttings and rooting them at home. The process for both is pretty much the same.
Hardwood u0026 Softwood Cutting Process
- Fill your pots with a sterile growing medium.
- Find a good spot for the plants to live for the next few months.
- You will want your cuttings to receive bright, but indirect light.
- To take a softwood cutting, find a branch that is still fresh and pliable.
- This cutting should be about 6 inches long.
- Snip this section from the shrub.
- Remove leaves from the bottom third of the cutting.
- To take a hardwood cutting you will be looking for a longer cutting.
- Strip the leaves from the bottom half of this cutting as well.
- Dip your cuttings in some rooting hormone powder.
- Stick the cuttings in the center of your prepared pots.
- From this point on, you will want to keep the soil moist but not too wet.
- Place a plastic bag over the cutting to keep the temperatures warm
- You want to keep the humidity at a good point.
- Roots should form on cuttings in about a month.
- They may take slightly longer for hardwood cuttings.
- Gently tug on the cuttings, you should be able to tell if there are roots forming.
- Before you plant your cuttings in your garden, you will want to harden them off.
- Simply take your cuttings and leave them outside.
- Place them in a shady spot for about a week.
- This will allow them to so they can acclimate to the outdoor climate.
- If the temperatures get too cool at night, just bring the pots in at night.
Planting
Planting viburnum shrubs is a breeze. Once you have found a spot in your garden, you will simply want to dig a nice large hole.
Aim to make this hole about twice the size of the root ball of the viburnum. Situate your plant in the center of the hole and backfill with your garden soil.
Water thoroughly and keep your eye on your newly planted shrub for the rest of the growing season. These shrubs are drought-tolerant when they are well established. However, they will need to be watered more regularly when they are newly planted.
How to Grow
When growing viburnum shrubs, it’s important to meet their growth needs by providing an optimal environment. You’ll want to make sure to provide them with adequate sunlight, water, and fertilizer. You’ll also want to ensure that they are planted in the proper soil pH, as well as being planted in the right climate. Let’s dig a little deeper into each growth factor.
Light
Viburnums generally prefer to grow in full sun, although they are tolerant of some partial shade. If you live in a warmer climate, it is a good idea to make sure your viburnum is getting some shade in the afternoon to prevent water loss and crispy leaves.
Water
Viburnums need about one inch of water per week. This can either be from irrigation or rainfall. If you are not sure how much water your gardens get, I would suggest using a rain gauge to make sure your plants are getting the water they need.
While your viburnum is getting established in your garden, you will want to keep a close eye on your shrubs to make sure they do not dry out too quickly. Many viburnums are native to North America and will be drought-tolerant once they have matured.
Soil
When you are choosing a site to plant your viburnum, do your best to find some well-draining soil. Viburnums do not like to have wet feet.
As far as soil pH goes, viburnums are known to be acid-loving plants. However, there are some varieties that are more tolerant of a neutral pH. Do your homework before you purchase your shrubs. If you are not sure what your soil pH is, do a quick soil test.
Climate and Temperature
While this may differ slightly between species, viburnums are generally hardy in zones 4-8. They prefer moderate climates. If you live in a warmer climate, the shrubs will benefit from some afternoon shade.
Fertilizing
Viburnums do not require much when it comes to fertilizer. One application in the spring of a balanced fertilizer will suffice.
Making sure you have nice fertile soil is a great way to make sure that your viburnums are getting the nutrients they need. You can do this by adding compost to the surface of the soil once or twice a year.
Pruning
Pruning viburnums is not always a necessary garden task. If you would like to prune your shrubs to maintain a specific height, this is best done in the early spring.
Once the winter passes, remove any broken or weakened branches.
If you need to give your viburnum a really good pruning, or a renewal pruning, this is best done in the early spring as well. You will lose your flowers for the season, but your plant will be rejuvenated and back to its beautiful self next year.
Popular Varieties
There are a few popular varieties that you’ll see utilized in very different ways. Let’s take a look at some of the most popular varieties you are likely to see in display gardens.
‘Blue Muffin’
botanical name Viburnum dentatum ‘Blue Muffin’ | |
plant type Deciduous | |
bloom colors White | |
height 5-7 feet tall and 5-7 feet wide | |
hardiness zones 3-8 |
The beauty of this viburnum is in the berries. But before the berries arrive, this compact shrub will be covered with snowball-shaped creamy white flowers.
Once the flowers fade, the intense blue-colored berries arrive and cover the shrub in the late summer and will last well into the winter. Throughout the growing season, the foliage is a glossy dark green. The leaves will then turn to shades of gold or purple when the temperatures drop.
The blue muffin viburnum is a great choice for foundation plantings, as well as hedges and even smaller gardens.
‘Eastern Snowball’
botanical name Viburnum opulus ‘Sterile’ | |
plant type Deciduous | |
bloom colors White | |
height 11-12 feet tall, 9-10 feet wide | |
hardiness zones 3-8 |
If you are looking for a viburnum that will make a statement in your yard, the eastern snowball is a great choice! This shrub is covered in ball-shaped blooms that strongly resemble hydrangea flowers. The foliage is bright green during the summer but will fade to a nice shade of purple in the fall.
Plant the eastern snowball pretty much anywhere in your garden. The flowers will show themselves off no matter where you plant them. Try planting this viburnum as a backdrop to your perennial garden, or as a statement shrub near a window where you won’t miss the flowers.
‘Korean Spice’
botanical name Viburnum carlesii | |
plant type Deciduous | |
bloom colors Pink | |
height 4-8 feet tall and 4-8 feet wide | |
hardiness zones 4-7 |
‘Korean Spice’ viburnum is a moderately sized shrub, making it easy to fit into your gardens. The flowers are a light shade of pink, which begin blooming in the spring. Once the flowers have passed, red berries will appear. These berries will fade to black in the fall. The deep green foliage will turn to deep shades of red in the fall.
This Is a beautiful viburnum to plant near your patio or near your kitchen windows. Anywhere that you will be able to enjoy their fragrant flowers.
Pests
In general viburnums are pretty resistant to any major insect infestations. However, there are some common garden pests that may show up throughout the season that have been found on viburnums.
Aphids
Aphids are tiny green insects that suck the life out of the leaves and stems of your plants. These common pests are found in large quantities and can do a good amount of damage if they are left untreated. You may notice their damage by spotting the yellowing of leaves and stems, as well as by seeing the insects themselves.
You can spray aphids off your plants using the spray of your hose, or you can use insecticidal soap or horticultural oil to control them. Whichever method you choose, be sure to make contact with the aphids themselves.
Thrips
These small flying insects dine on plants the same way aphids do. Thrips will suck the life out of leaves, flowers, and berries. You may notice yellow splotches on otherwise healthy plant tissues.
Because thrips are flying insects, they can be a little tricky to control. Keeping your garden neat and your viburnums well cared for is the best way to keep your plants healthy and strong. If you find yourself with a thrip infestation, insecticidal soaps can work by smothering the thrips.
Scale
Scale insects can cause severe dieback if they are left untreated. The crawler stage of this insect will begin to emerge with new growth in the spring. These insects are so tiny at this stage you probably won’t see them.
Once the crawlers settle down and find a good feeding spot, they will begin to create a waxy coating around themselves which will protect them and also make control difficult.
You can pick the scale off of your viburnum with your hand. If you have a severe infestation, it is best to prune the branches right off your plant. Horticultural oil sprayed in the spring can also help to get rid of the crawlers before they create their armor.
Spider Mites
These pesky insects will suck on the tissues of your plant. They are small, and you likely will not notice the insects themselves. What you will notice is the webbing they create to protect themselves and their eggs.
You will notice small spots on the bottoms of the leaves. The damage will spread to the tops of the leaves as the spider mite population booms.
Spider mites are attracted to plants that are under stress. Prevention is your best measure here. Keep your viburnums well-watered to help keep these insects at bay. Spray your hose at your viburnum to knock the insects off of the plant. If this does not work, you can use an insecticidal soap or horticultural oil.
Viburnum Leaf Beetle
This beetle is probably the largest threat to viburnums when it comes to insects. The viburnum leaf beetle feeds exclusively on viburnums. The larvae as well as the adult beetles will nibble on leaves, leaving large holes throughout.
Using horticultural oil is your best bet. If you have a really bad infestation, imidacloprid applied as a drench will work for you.
Diseases
Similar to pests, these shrubs can be affected by a few different diseases. The following diseases are those that you will be most likely to encounter, as well as a few tips on preventing them from taking over your plants in the first place.
Canker
Canker is caused by a fungus called Botryosphaeria. Like many other diseases and ailments, canker is more prevalent on viburnums that are stressed.
If your viburnum has any wounds, this is where you will see cankers forming. The fungus will work itself into the wound and cause sunken areas. As these cankers multiply, they will eventually connect to one another and girdle the plant. This will result in plant death.
Prevent cankers by keeping your viburnums watered. If you see cankers on your shrub, your best bet is to prune the infected branches and burn them.
Powdery Mildew
This is a common garden disease. Powdery mildew typically shows up when the weather gets more humid. The extra moisture in the air promotes fungal growth, and bam, you’ve got yourself some powdery mildew. Luckily powdery mildew won’t be too detrimental to your viburnums.
Keep your garden clean by removing plant debris from the soil, and also by removing leaves from within the base of the shrubs. This will help to prevent powdery mildew from developing. If it is too late for prevention, horticultural oil can help, as can other fungicides you can find at your garden center.
Root Rot
This is another fungal disease, but this one affects the root system of your viburnum. You may not notice any symptoms of root rot, other than the plant suddenly dying.
If you do notice that your viburnum is suddenly drooping, has yellow leaves all over, or is dropping its leaves suddenly, you may have root rot. These symptoms probably sound a lot like a plant that has too much water, or too little water.
The way to find out if it is fungal root rot is to peel away some bark from the base of the plant. If you see white fungus beneath the bark- you have fungal root rot.
There is not much you can do once a plant has become infected with root rot. Preventing it is easily done with cultural practices. Ensuring that your viburnum is properly watered is a good way to keep this disease from taking hold.
Plant Uses
If you are looking to create a very low maintenance garden that is not only beautiful but also benefits the environment, adding viburnums is a great place to start. These shrubs do not require much fertilizer, or water. Their berries provide food for birds, and their flowers attract many beneficial pollinators.
Viburnums make for great hedges or privacy screens. Not all viburnums are evergreen, so if you are looking for year-round privacy make sure you choose an evergreen viburnum.
Viburnums are also beautiful specimen plants. The flowers are showy, and many species and varieties have berries that are equally as beautiful providing year round interest for your garden.
Frequently Asked Questions
Why isn’t my viburnum blooming?
If you are noticing that your viburnum is not pumping out the amount of flowers you were hoping for you should check its growing conditions.
First, viburnums bloom best when they are planted in full sun. This means at least 6 hours of sun. But really 8-10 is better. These plants do benefit from a little bit of afternoon shade if you live in a warmer climate. This will help to keep the plant from losing too much water. But, if you are trying to get your viburnums blooming you will want to focus on the sunlight.
Second, check the amount of water your plant is getting, as well as the soil type your viburnums are growing in. Viburnums do not like having wet roots, if the soil is not draining well enough your plant may not produce flowers.
A basic fertilizer will help your plant to produce good healthy vegetative and floral growth. Apply fertilizer in the spring.
Are viburnums toxic?
Viburnums do not hold major toxic qualities. There are some species that produce berries that are made for jam. However, there are also some species that produce berries that are slightly toxic. So to keep things on the safe side, do not ingest any part of the viburnum plant.
Is viburnum invasive?
In some areas of the United States viburnums are on the invasive plant list. This is a new finding. It is unknown why the plants are spreading rapidly in some areas.
The viburnums you purchase from a garden center likely will not take over your garden. They will grow as expected. Do a bit of research to see if viburnums are considered to be invasive in your area, and check which species are invasive.
Can I grow viburnum in containers?
Yes! This is a great option if you do not have a lot of garden spaces that get a lot of sunlight. You will need quite a large pot though. When you get started choose a pot that is twice as wide as the root ball of your viburnum. Use good quality potting mix, and situate your pots in full sun!
Final Thoughts
Viburnums are beautiful flowering shrubs. I love them for so many reasons. Their size and shape, their stunning flowers, and their vibrant berries make this shrub a must-grow in your garden. If you are looking for a low-maintenance plant for your gardens, I urge you to give a viburnum a try! Your garden and your local wildlife will thank you!